OFF THE COB INVESTIGATES THE MUTANTS OF MAIZE

NOVEMBER 2014

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Today, Off the Cob spoke with Dr. Gerry Neuffer, professor emeritus at the University of Missouri, about his work on the mutants of maize and their importance for research.

Neuffer first explained how he his way to this sort of work.

“Every new mutant phenotype holds a key to understanding some important biological process,” Neuffer explained. “I discovered that the natural frequency of mutation in maize could be increased a thousand-fold by treating corn pollen with the chemical agent ethyl methylsulphonate in paraffin oil and, as a consequence, generated literally thousands of new mutants. I saw in my mutant collection the potential for great advances in theoretical genetics, plant breeding, biology, medicine, and production agriculture. With the help of funding agencies, commercial companies, USDA, the University of Missouri Agricultural Experiment Station and many helpful colleagues, we were able to make important discoveries and expand the previously known mutant collection immensely.”

He then spoke on why mutants play an important role in research.

“Mutants are important in understanding gene function,” said Neuffer. “By knocking out individual genes, we were able get insight into how the plant has changed in morphology or in response to environmental stimuli. This gives researchers tools to understanding plant biology. But more important by changing an active gene from one level of function to a higher efficiency or to another different function we got the variation that is so important to crop production or to evolutionary survival. This was our goal! “

With so much data generated, Neuffer had to work meticulously to catalogue his findings.

“I took as many pictures as possible because there were just too many mutations for one person to accurately describe in written text. We built our own Mutant Data Base to keep all the information, which we periodically shared with MaizeGDB. We also published two editions of Mutants of Maize, which were an encyclopedic compilation of images of known and new mutants. Additionally, we sent seed to the Maize Genetics Seed Storage Cooperative so that researchers could have access to the material.”

Neuffer shared his recollections of his favorite maize mutant, although he acknowledged the difficulty of choosing only one.

“The most exciting mutants were the ones that dramatically resembled known leaf lesion diseases; we called these ‘Disease Lesion Mimic Mutants.’ These mutants show great promise for providing new ways to solve problems of plant disease susceptibility because they provide a wide range of disease like symptoms in the absence of a pathogen. The most amazing was the fact that one of the Lesion mutants, Les22, was found to have the same genetic code as the rare Porphyria skin disease that is so disabling in humans. Others of these Lesion mutants are providing important information about cell death signaling that relates to aging in all creatures.

“The dominant mutants are especially exciting because they provide us with new mutants that were rarely ever seen before and can now be found often enough to be workable because of chemical mutagenesis. They are most promising. Who can tell what the next exciting dominant mutant will be? There are still more to be found. Notably, they are called dominant because only one copy of the allele is needed to see the change in the plant or its response to the environment.”